Background: High blood cholesterol accelerates the progression of atherosclerosis that is an asymptomatic process lasting for decades. Rupture of atherosclerotic plaques induces thrombosis that results in myocardial infarction or stroke. Lowering cholesterol levels is beneficial for preventing atherosclerotic cardiovascular disease (ASCVD). Methods: Low-density lipoprotein (LDL) receptor (LDLR) was used as the bait to identify its binding proteins in the plasma, and the coagulation factor prekallikrein (PK, encoded by the KLKB1 gene) was revealed. The correlation between serum PK protein content and lipid levels in young Chinese Han was then analyzed. To investigate the effects of PK ablation on LDLR and lipid levels in vivo , we genetically deleted Klkb1 in hamsters and heterozygous Ldlr knockout mice, as well as knocked Klkb1 down using adeno-associated virus-mediated shRNA in rats. The additive effect of PK and PCSK9 inhibition was evaluated as well. We also applied the anti-PK neutralizing antibody that blocked PK and LDLR interaction to mice. Mice lacking both PK and Apolipoprotein e ( Klkb1 -/- Apoe -/- ) were generated to assess the role of PK in atherosclerosis. Results: PK directly bound LDLR and induced its lysosomal degradation. The serum PK concentrations positively correlated with LDL cholesterol levels in 198 young Chinese Han adults. Genetic depletion of Klkb1 increased hepatic LDLR and decreased circulating cholesterol in multiple rodent models. Inhibition of PCSK9 with Evolocumab further decreased plasma LDL cholesterol levels in Klkb1 -deficient hamsters. The anti-PK neutralizing antibody could similarly lower plasma lipids through upregulating hepatic LDLR. Ablation of Klkb1 slowed down the progression of atherosclerosis in mice on Apoe -deficient background. Conclusions: PK regulates circulating cholesterol levels through binding to LDLR and inducing its lysosomal degradation. Ablation of PK stabilizes LDLR, decreases LDL cholesterol and prevents atherosclerotic plaque development. This study suggests that PK is a promising therapeutic target to treat ASCVD.

BackgroundThe cardiac autonomic nervous system plays an essential role in epicardial ganglionated plexi (GP) regulation of atrial fibrillation onset and progression. To date, the activity of GP and the function of the cardiac autonomic nervous system are not well understood. The aim of this study was to determine alterations in epicardial GP cholinergic nerve, adrenergic nerve, and nerve growth factor expression using rapid atrial pacing to induce atrial fibrillation in canines.Material/MethodsNine healthy adult beagles were divided into two groups: the pacing experimental group (n=6) and the sham-operation control group (n=3). For the pacing group, high frequency pacing of the left atrial appendage was performed for eight hours. In the control group, electrodes were implanted without rapid atrial pacing. Immunocytochemistry was used to identify neurons positively expressing tyrosine hydroxylase, choline acetyl transferase, nerve growth factor and neurturin.ResultsAfter successfully establishing a rapid atrial pacing of the left atrial appendage induced atrial fibrillation model, we found that expression of choline acetyl transferase, tyrosine hydroxylase, nerve growth factor, and neurturin was significantly higher in the rapid atrial pacing group than the control group (p<0.05).ConclusionsIn our model, incremental excitability of both the adrenergic and cholinergic nerves led to frequent incidents of atrial fibrillation, which were possibly due to an imbalance of autonomic nerve factors in the epicardial GP during acute atrial fibrillation.

Background: This retrospective study assessed the precision of noninvasive prenatal testing (NIPT) in detecting microdeletion/microduplication syndromes (MMSs) and nonsyndromic copy number variations (CNVs). Methods: The study included 19,086 singleton pregnancies screened on NIPT using high-throughput sequencing. Pregnancies with CNVs on NIPT underwent amniocentesis for karyotyping and CNV sequencing (CNV-seq). We analyzed pathogenic MMSs and nonsyndromic CNVs separately, dividing the CNVs into subgroups based on fragment size and fetal ultrasound findings. Results: A total of 170 abnormalities were detected by NIPT, of which 113 (66.5%) underwent invasive testing. The positive predictive value (PPV) of CNV-seq for all types of CNV detected by NIPT was 35.4%, with PPVs of 61.5 and 27.6% for pathogenic MMSs and nonsyndromic CNVs, respectively. PPVs for NIPT showed different values depending on gestational characteristics, with the highest PPV for NIPT in the group with increased nuchal thickness (66.7%) and for the abnormal ultrasound group (57.1%). CNVs ≤5 Mb with normal ultrasound findings were generally associated with a healthy fetus. Conclusion: NIPT can detect chromosomal aberrations in the first trimester, with high performance for MMSs. However, due to the low PPV for nonsyndromic CNVs, and the good pregnancy outcome in most cases, the introduction of expanded NIPT would cause an increase in unnecessary invasive procedures and inappropriate terminations of pregnancy.

Background HMGCR, SCAP, SREBF1, SREBF2 and TBL2 are well-known genes that are involved in the process of lipid metabolism. However, it is not known whether epigenetic changes of these genes are associated with lipid metabolism. In this study, the methylation levels of the HMGCR, SCAP, SREBF1, SREBF2 and TBL2 genes were analyzed between samples from a hyper-low-density lipoprotein cholesterolemia (hyper-LDL) group and a control group to examine the association between the methylation levels of these genes and the risk of hyper-LDL. Methods In this study, a case-control approach was used to explore the association between DNA methylation and hyper-LDL. The DNA methylation levels of HMGCR, SCAP, SREBF1, SREBF2 and TBL2 genes and 231 CpG sites in the promoter regions of these genes were measured in 98 hyper-LDL participants and 89 participants without hypo-LDL. Results Compared with participants without hyper-LDL, patients with hyper-LDL TBL2 gene had lower methylation levels (11.93 vs. 12.02, P = 0.004). The methylation haplotypes with significant abundance in the TBL2 gene are tcttttttttt (P = 0.034), ctttttttcct (P = 0.025), ctctttctttt (P = 0.040), ccttttttttt (P = 0.028), and tctttttttttttttt. Conclusion The study demonstrates that participants with hyper-LDL have lower methylation of TBL2. The results suggest that DNA methylation of TBL2 can decrease the risk for hyper-LDL in humans.

Background Coronary heart disease has become the leading cause of death in developed countries, and dyslipidemia is closely associated with the risk of cardiovascular disease. Dyslipidemia is caused by the abnormal regulation of several genes and signaling pathways, and dyslipidemia is influenced mainly by genetic variation. AMFR, FBXW7, INSIG1, INSIG2, and MBTPS1 genes are associated with lipid metabolism. In a recent GWAS study, the GRINA gene has been reported to be associated with dyslipidemia, but its molecular mechanism has not been thoroughly investigated. The correlation between the DNA methylation of these genes and lipid metabolism has not been studied. This study aimed to examine the relationship between the DNA methylation of these genes and the risk of dyslipidemia by comparing the methylation levels of dyslipidemia and control samples. Methods A case-control research method was used in this study. The patient’s blood samples were collected at the Heart Center of the First Affiliated Hospital of Xinjiang Medical University. In the Xinjiang Han population, 100 cases of hyperlipidemia and 80 cases of the control group were selected. The two groups were age and gender-matched. Quantitative methylation analysis of CpG sites in the gene promoter regions of six genes was performed by Solexa high-throughput sequencing. Results The DNA methylation levels of 23 CpG sites in six genes were shown to be associated with hyperlipidemia, and a total of 20 DNA methylation haplotypes showed statistically significant differences between the two groups. When compared with the control group, the dyslipidemia group had significantly higher levels of methylation in the GRINA gene (2.68 vs 2.36, P = 0.04). Additionally, we also discovered a significant methylation haplotype of GRINA (P = 0.017). Conclusion The findings of this study reveal that the DNA methylation of GRINA increases the risk for dyslipidemia in humans.